1. Field of the Invention
The invention relates to a belt-like tension element, a guiding device and a driving device for the tension element, as well as to a conveying device including the tension element, for a handrail, guiding system, driving system, and a conveyor for an escalator or a people-mover with a cross-section formed by a first, in particular upper cross-sectional part, and a second, in particular lower cross-sectional part, whereby the first cross-sectional part is adapted to form a handle for individuals to be transported with the escalator or people-mover. Furthermore, it relates to the application of the belt-shaped tension element as a conveyor belt or handrail such as an application of the belt-shaped tension element as a conveyor belt particularly for a belt conveyor, or an application of the belt-shaped tension element as a handrail for an escalator or a people-mover.
Tension elements of the type defined by the invention are employed in the prior art, for example in belt conveyors, and as handrails for escalators and people-movers or the like.
2. Discussion of Background Information
Belt conveyors are known to be include a revolving endless belt that is partly supported by reversing rollers arranged on the two end sections of the belt opposing one another. Merchandise is conveyed by the so-called upper strand of the belt; its lower strand returns empty for receiving more merchandise. In belt conveyors, individual guiding rollers have been employed heretofore for preventing the belt from migrating sideways. Endless conveyor belts consist of rubber or plastic depending on whether piece goods, non-wearing or sticky bulk materials are conveyed at up to 100° C., and are equipped with fabric or steel inserts for their reinforcement.
Handrails for escalators, people-movers or similar applications are employed as safety elements for transporting people. For this purpose, the handrail has to allow the rider to safely grip such elements, and must be capable of withstanding the dynamic stress or environmental influences while in operation without suffering damage. Handrails known in the prior art have a C-shaped cross-section and are normally built up from a multitude of different materials so as to satisfy such requirements. The surface of the handrail that the rider can touch is usually made of an elastomer mixture. Furthermore, the molding of the handrail protects all components arranged beneath it against various environmental influences, and therefore has to be resistant to such influences. Reinforcing inserts such as, for example fabric cords, mixtures reinforced by short fibers etc., are normally used for increasing the dimensional stability of the cross-section of the handrail. An adequately high rigidity of the lip, i.e. stiffness of the lateral areas of the handrail, can be achieved in this way as well. It is expected that the handrail will maintain its cross-sectional shape throughout its useful life, i.e. the cross-section may neither increase nor decrease excessively in the course of its service life. In addition to strong development of noise if the handrail is contacted, any such reduction would lead to generation of heat, driving problems, and finally to destruction of the handrail. The consequence of any increase, on the other hand, would pose a hazard in that the rider could get caught between the lip of the handrail and the guide rail, on the one hand, and the handrail could jump out of the guide rail on the other.
Furthermore, over its cross-section, the handrail contains so-called tension carriers for receiving longitudinal forces. Such tension carriers have to exhibit a defined minimum tearing strength also in the joint area.
Finally, the so-called sliding layer forms the contact surface of the handrail with its guiding and driving systems.
A handrail with a C-shaped cross-section is known, for example from DE 198 32 158 A1. This handrail consists for its major part of a thermoplastic elastomer, and the surface pointing inwards has a section made of a material having a lower hardness than the thermoplastic elastomer. The ends of the C-shaped cross-section, which are referred to as the nose areas, are made of a harder elastomer and are forming channels for receiving guiding means. The driving roller is arranged in a manner such that it comes into contact with the soft elastomer, the latter forming part of the inner surface and being centrally arranged in the cross-section. A profile element is employed as the guiding means that is substantially filling the cavity formed by the C-shaped profile, and partially enveloped by the two nose areas. The inner surface of the handrail facing the guiding element may be plane or profiled as well. The drawback thereof is that a multitude of different elements are employed for building up the cross-section, and, furthermore, that in addition to the driving means resting against the inner surface of the handrail, a driving means is present also on the outer surface facing the rider, which causes the latter surface, which is visible while the system is in operation, to be stressed accordingly, and the driving means to leave score marks on the surface, which substantially reduce the service life of the handrail.
A guiding system for a handrail is known from DE 198 29 326 C1. This guiding system is particularly used for handrails with a C-shaped cross-section in the areas of reversal, and is built up from a multitude of individual elements that require continuous maintenance to some extent, for example such as servicing of the antifriction bearings contained therein.
Furthermore, a handrail drive is known from DE 198 50 037 A1, where the handrail has to be flexed across its back and the visible surface of the handrail again comes directly into contact with the driving system. Such a stress causes fouling not only of the back of the handrail, but leaves behind the aforementioned score marks on the surface of the handrail, whereby the negative flexure may cause growth of cracks and failure of the handrail as well. Moreover, it is necessary in connection with this driving system to pretension the handrail so as to be able to transmit the additional driving torque. It is a drawback in that connection that the useful life of the handrail is reduced by excessive pretension of the handrail due to increased de-lamination, on the one hand, and change in the length of the handrail on the other. For avoiding any direct contact with the driving pulley of the handrail, a hose is arranged on the pulley, and the required pressure is transmitted from the driving pulley to the handrail with the help of such a hose. The hose is filled with air, which ensues the problem that in case of any leakage of the hose, the handrail itself is again in direct contact with the driving pulley.